Tension device for sewing-machines.



W. 0. MEYER. TENSION DEVICE FOR SEWING MACHINES. APPLICATION FILED SEPT.1, 1909.

1,030,743, Patented June 25, 1912.

4 SHEETS-SHEBT 1.

/9 I O j V W. G. MEYER.

TENSION DEVIbE FOR SEWING MACHINES.

APPLICATION FILE-D SEPT. 1, 1909.

1,030,743., I Patented June 25, 1912.

4 BEEETS-SHEET 2.

W. 0. MEYER. TENSION DEVICE FOR SEWING MACHINES. 1

APPLICATION FILED SEPT. 1, 1909. 1,030,743, Patented June 25, 1912.

4 SHEETS-SEE 3.

mwww M W. 0. MEYER. TENSION DEVICE FOR SEWING MACHINES. I

APPLIOATION FILED SEPT. 1, 1909.

- L9 Patented June 25, 1912.

4 BHEE'ES-SHEET 4.

lawman- IWILLIAM C. IEEYER, 015 BOSTON, MASSACHUSETTS, ASSIGNOE TO UNITED SHOE MACHINERY COMPANY, OF PATEBSON, NEW JERSEY, A CORPORATION OF JERSEY.

TENSION DEVICE FOR SEWING-MACHINES.

Specification of Letters Patent.

Application filed September 1, 1909. Serial No. 515,673.

To all whom "it may concern:

Be it known that I, VVILLIAM C. Mariam,

a citizen of the United States, residing at Boston, in the county of Suifolk and State of Massachusetts, have invented certain new anduset'ul Improvements in Tension Devices for Sewing-Machines; and I. do here by declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. I The present invention relates to an improved tension device for sewing machines and is designed particularly for use on wax thread shoe sewing machines which form a chain stitch, although the invention is capable of use on other types of sewing machines.

Inthe operation 01'' sewing machines, and particularly wax-thread chain-stitch sewing machines, it has been found that the tension which must be exerted on the thread to produce the best results varies with the speed at which the machine is operated, a heavier tension ordinarily being required to pro duce a tight seam when the machine is operated at a slow speed than when the machine is operated at a high speed.

The principal object of the present invention is to provide means whereby the tension on the thread is controlled automatically by the speed of the machine so that the desired amount of tension may be exerted upon the thread at all times' With this object in view a feature of the present invention contemplates the provision, in a sewing nmchine, of means responsive to variations in the speed of the machine and operating to vary the tension on the thread when the speed of the machine varies.

Broadly considered this feature of the present invention co1-i'tem lates the provision of any suitable meansoperating in response to variations in the speed of the machine to vary the tension on the thread. In the preferred torm of this feature, of the invention, however, a tension device for the thread is provided and a governor therefor which is driven by the machine and which operates the tension device to vary the ten sion on the thread when the speed of the machine varies. in accordance with this feature oi the invention the tension on the thread may be either increased or diminished as the speed of the machine increases.

In machines oi? the type illustrated in the drawings accompanying this application, it has been found that the best results ean be secured when the tension on the thread is decreased as the speed of the ma-- chine increases and increased as the speed of the machinedecreasos. iocordingly, in the illustrated embodiment it the invention hereinafter described, the governor for the tension device is arranged to operate the tension device so as to vary the tension on the thread inversely with the speed of the machine. v

Other objects of the present invention are tosimplify and improve the construction and arrangement of the various parts of tension devices for sewing'machines and particularly tension devicesmi that type which are adapted to exert diticrent degrees of tension on the thread during each cycle of operations of the sewing machine.

With these objects in view the present invention also consists in'cert'ain devices combinations and ar 'angenients of parts lriercinatter described and claimed the advantages of which will be obvious to those skilled in the art from the i ollowing description.

The several features of the present inven tion-will be clearly understoodltrom an in spection of the accompanyingdrawings in which Figure l is a view in side elevation, with the cam shaft shown in section, of a chainstitch shoe-sewing machine with the preferred embodiment of the invention applied thereto. Fig. 53 a sectional elevation of the machine looking tion trri ig. 1. Fig. 3 is a view in front elevation, partly in section, and on an enlarged scale, of the tension and tension regulating; devices. Fl is a view in side .clcvatimi of the tension and tension regn parts illustrated in Fig. 5 and Fig. 7 is a detail edgevicw, partly in section, oi the tension truck.

The machine illustrated. in the drawings is a curved hook needle shoe sewing machine oi the same general type as that illustrated in the patent to French Itieycr, lie.

in the oppositedirec- 412,704, dated October 8, 188-9, although the various parts are somewhat differently arranged and are actuated by somewhat different mechanism. 'Inasmuch'as the present invention relates principally to the ten-,

sion and tension regulating devices, the

construction and arrangement of the other arts need be but briefly described. It may e said, however, that the stitches are tightened or set when theneedle is in the work by the act-ion of the take up which pulls the loop of thread last drawn out by the needle tightly around the shank of the needle. This is the mode of operation of the particular machine. In the machine illustrated in. the drawings, however, a uniform and relatively light tension is exerted uponthe thread during the retracting stroke of the needle and a comparatively heavy tension during the action of the take up whereas in the patented machine a uniform tension is exerted upon thethread at all times.

Referring now to the drawings 1 indicates the curved hook needle, 2 the needle guide, 3 the thread arm, 4 the looper 5 the take up, 6 the auxiliary take" up, and 7 the tension truck. The thread 8 leads from the back of. the machine through the tube 9 and passes under the guide roll 10 over the guide roll 11, around the tension truck 7,

over the guide roll 12, under the auxiliary take up 6, over the main take 'up' 5 and brake'disk 14 secured to the shaft upon.

which the tension truck 7 is fixed. These brake shoes are pivotally mounted at the opposite ends of an arm 15 pivotally mounted midway between its ends upon the outer end of a brake carrying lever or arm 16. The arrangement of the brake shoes 13 and lever 16 is such that a downward movevment of the lever around 1ts pivot presses the shoes against the disk 14 and thereby retards its rotation so as to place the thread leading from the tension truck to the work under tension. The brake carrying lever '16 isjorced downwardly so as to produce the desired amount of tension on the thread by means of a spring 17 and suitable connections between the spring and the lever. These connections will be hereinafter described.

The. means illustrated in the drawings for varying the tension on the thread when the speed of the machine varies consists of a governor driven from the cam shaft of the machine, and intermediate connections to the spring 17, the arrangement being such that when the speed of the machine increases the tension of the spring 17 is diminished and when the speed of the machine diminishes the tension of the'spring' is increased.

The governor consists of two weights 18 which are supported at the center joints of toggle levers 19 and are acted upon by coiled springs 20, the tendency of which is to draw the weights toward each other. The lower ends of the toggle levers 19 are pivoted-to a collar 21 fast upona vertical shaft 22, while the upper ends of the toggle levers are pivoted to a collar 23 upon a sleeve '24 mounted to slide longitudinallyon the shaft 22. The shaft is driven from thecam shaft 25 of the'machine by intermeshing bevel.

gears so that the speed of the shaft 22 varies with that of the machine. It will be obvious from an inspection of the drawings that the sleeve24 Wlll fall as the speed of the machine increases and will rise as theispeed of the machine decreases. This movement'of the sleeve 24 is utilized to control the tension of the spring 17 and to this end the sleeve is arranged to engage the rear end of a lever 26, the forward end of which is provided with a sleeve 27' the lower end of which forms an abutment for the upper end of the spring 17. The spring 17 is thus compressed more or less, depending upon.

the speed of the cam shaft 25 and shaft 22 driven therefrom, and consequently the amount of tension on the thread is controlled by and is dependent or the speed at which the machine is operated. To enable the tension of the spring 17 to be adjusted manually by the operator to give the desired tension on the threau at any given speed, the sleeve 27 is screw threaded in the lever 26 so that itcan be adjusted vertically therein.

The connections between, the spring '17 and the brake carrying lever 16' comprises a. rod 28 around which the spring '17 is coiled and two levers 29 and 30 which are acted upon by the rod 28 and which engage the lever "16. Two actuating levers 29 and 30 are provided in order that the pressure on the brake carrying lever 16 maybe varied during each cycle of operations of themachine to cause a. heavier tension to be ex- 'erted on the thread during the stitch setting stroke of the take up than during the thread drawing stroke of the needle. When both levers 29 and 30 are in engagement with the lever 16 a heavy tension is exerted upon the thread. To remove a portion of the pressure on the lever 16 so as to give a comparatively light tension on the thread during the retracting stroke of the needle, the lever 29 is raised during a portion of each cycle of operations of the machine and to accomplish this an arm 31 is provided which extends beneath the rearwardly projec ting end 32 of the lever 29. The arm 31 a is secured to a, rock shaft 33 whichis provided with a projecting tooth 34: engaging a correspondingly shaped recess in the hub of a cam actuated lever arm 35. To permit both levers 29 and 30 th be acted upon the spring pressed rod: 28 and also to 'gpermit" the lever 3.0 to be moved, independently of the lever 29, a bar 36, best shown in Fig. 6, is pivotally secured, at one end to the rear end of the lever 30 andat its other end is provided. with a rounded projection which fits a corresponding recess in the rear end-of the lever 29. The rod 28 at its lower end is seated in a recess in the bar 36 midway between the twblevers 29 and 30. By.

levers 29 and 30 and the lever"29 can be.

raised without removing the pressure of the spring from the lever 30.

It is sometimes desirable to adjust either a the amount of the light tension or the heavy tension independently of the other and to enable this to be done each of the levers 29 and '30 is provided with an abutment 37 to bear on the brake carrying lever 16, which abutment is longitudinally adjustable in the lever. Each of these abutments consists of a projection from a slide 88 mounted in a suitable guideway and provided with rack teeth meshing with teeth on the hub of a hand lever 39, which hand lever 39 is pivotally mounted on one of the levers 29 and 30 and is provided with a spring pressed locking pin 40 arranged to engage a series of teeth on a segment 41 secured to the lever. By means of the handles 39, the abutments 37 can be readily adjusted by the operator to vary the proportion of the light to the heavy tension or to change the amount of both tensionsindependently of any adjustment-of the spring 17.

\Vhile the machine is O'pelntll'lg to sow a scam the lever 30 remains contimaiusly in .engagement'with the brake carrying iever 16 so as to produce a predetermined uniform tension on the thread. Baring the stitch setting stroke of the take up, the lever- :29 is also in engagement with the brake carrying lever 16 so as to produce a comparatively heavy tension on the thread but during the loop drawing stroke of the needle the lever 29 is raised and the thread is held under light tension by the action of the lever 30. 0 When the machine is stopped and the work is to be Withdrawn from the machine it is desirable that the thread be relieved of all tension, and to secure this result the ma.

shaft of the machineis rotated by hand in a reversed direc'ti tn, raises the brake carrying lever 16 so its to lift the brake shoes 13 out of engagementwith the'dislrl l. This tension release comprises a swinging link orarm 42 such as is commonly employed in mechanisms of this character, which is adapted to be swung from the position illustrated in Fig, 4qto that illustrated in Fig, 1 upon a reversal in the direction of rotation of the cam shaft 25. 'l-hg arm 42 is pivotally mounted upon the lower end of a bell crank lever the forward horizontal arm of which is provided with an, adjustable set screw tdiarranged to engage a projection d5 on the brake carrying lever 16.

The nature and scope of the present invent-ion having'been indicated and a con struction embodying the several features thereof in their preferred form having been specifically described what is claimed is 1-. A sewing machine, having, in combination, stitch forming devices, and means responsive to variations in thespeed of the machine operating during the continued op eration of the machine in sewing a seam to vary the tension on the thread when the speed of the machine varies.

2. A sewing machine, having, in combi threadwhen the speed of the machine varies.

4. A sewing machine,- having, in combination, stitch fdrming devices, a tension device including a brake, a spring acting on the brake and means responsive to variations in the speed of the machine operating dur ing the continued operation of the machine in sewing a seam to vary the tension of the spring when the speed of the machine varies.

5. A sewing machine, having, in combination, a tension device including a brake, a spring for actuating the brake, means whereby the tensio of the spring can be adjusted manually and a governor operating during the continued operation of the machine in sewing a seam to vary the tension of the spring when the speed of the machine varies.

6. A sewing machine, having, in combina tion, stitchforming devices, a tension device including a brake. a spring acting on the brake, an abutment for the spring, and a governor operating during the continued operation of the machine in sewing a scant to move said abutment to vary the tension of thespring when the speed of the machine varies.

7. A sewing machine, having, in combinationystitch forming devices, a tension device including a brake, a spring acting on the brake, an abutment for the spring, a carrier in which the abutment is mounted so as to be capable of a. manual adjustment to vary the tension of the spring, and means responsive-to variations in the speed of the machine operating tomove the carrier to vary ,the tension of the spring when the speed of'the machine varies.

8. A sewing machine, having, in combination, stitch forming devices, a tension device including a brake, a brake carrier, a lever for actuating the brake carrier, a spring acting on the lever, and an abutment on the lever arranged t-o bear on the brake carrier and adjustable longitudinally of the .lever' to vary the tension on. the thread.

9. A chain stitch sewing machine, having,

in combination, stitch forming devices, in-

cluding a hooked needle and a stitch setting take up operating while the needle is in the work, a spring and devices actuated thereby to produce tension on the thread, means for causing the spring to produce relatively light tension on the thread during the loop drawing stroke of the needle and relatively heavy tension during the stitch" setting stroke of the take up and means operating automatically to vary the tension of the spring when the speed of the machine varies.

10. A sewin machine, having, in combination, stitch torming devices, a tension device including a brake, a brake carrier, two

levels for actuating the brake carrier, means for exerting spring pressure onthe levers, connections between the levers and carrier adjustable to vary the tension on the thread, and means for raising one lever during each cycle of operations ot the machine.

11. A sewing machine, having, in combination, stitch forming devices, a tension device including a brake, a brake carrier, a spring for actuating the brake carrier, two sets of connections between the brake carrier and spring and means for throwing one set of connections out of operation during each cycle of operationsof the machine.

12. A sewin machine, having, in combi nation, stitch torming devices, a tension device including a brake, a spring for actuating the brake, two sets of connections between the brake and spring, means for throwing one set of connections out of op eration during each cycle of operations of the machine and means for varying the tensionof the spring in response to variations in the speed of the machine.

13. A sewing'machine, having, in combi nation, stitch forming devices, a tension dcyice including a brake, a brake carrier, two levers for actuating the brake carrier, :1 bar braking pressureduring the stitch setting stroke of the take up.

15. A chain stitch sewing machine, hav ing, in combination, stitch forming devices including a hook needle and a stitch setting take up operating while the needle is in the work, a tension device including a brake, a spring, connections between the spring and the brake, and means .for actuating said connections to produce relatively lightbraking pressure during the loop drawing stroke. of the needle and relatively heavy braking pressure during the stitch setting stroke of the take up.

16. A chain stitch sewing machine, having, in combination, stitch forming devices including a hookneedle and a stitch setting take up operating while the needle is in the work, a tension device including a brake, a spring, an'd means for causing the spring to act on the brake to produce relatively light braking pressure during the loop drawing stroke of the needle and relatively heavy' braking pressure during the stitch setting stroke of the take up. v

17 A sewing machine, having, in combination, stitch forming devices, a tension device including a spring, means whereby the tension of the spring may beadjusted manually, and means driven by the machine acting during the continued operation of the machine in sewing a seam to vary the ten- 7 sion of the spring when the speed of the machine varies.

18. A chain stitch sewing'inachine, having, in combination, stitch forming devices, including a hooked needle, and a stitch setting take-up operating while the needle is in' the work, a spring and devices actuated thereby to produce tension on the thread,

and means for causing the spring to' produce relatively light tension on the thread during the loop drawing stroke of the needle and relatively heavy tension during the stitch setting stroke of the take-up.

' WILLIAM C. MEYER.

lVitnesses:

Tim L. FISH, l\'l.\RGARET L. GILMAN. 

